MySQL的 - 通過

Question

天

組比較計數我有以下查詢：

select 
    DATE_FORMAT(created_at,'%d %M') as day, 
    count(*) as Total, 
    count(content_sentiment = 0) as Neutral, 
    count(content_sentiment < 0) as Negative, 
    count(content_sentiment > 0) as Positive 
from Master 
where content_sentiment IS NOT NULL 
GROUP BY DAY(created_at) 
; 

這一點讓我：

day   total Neautral Negative Positive 
------------------------------------------------------------ 
01 August 9037 9037 9037 9037 
02 August 6439 6439 6439 6439 
03 August 5922 5922 5922 5922 
04 August 5382 5382 5382 5382 

的總價值應該是一個總和的正面，中性和負面的不是即時猜測，因爲每個查詢都會獲得整個表的總數，而不是按天分組。

如何爲每個正面，中性和負面值包含一組？

Answer 1

您需要有條件聚集：

... 
count(*) as Total, 
SUM(CASE WHEN content_sentiment = 0 THEN 1 ELSE 0 END) as Neutral, 
SUM(CASE WHEN content_sentiment < 0 THEN 1 ELSE 0 END) as Negative, 
SUM(CASE WHEN content_sentiment > 0 THEN 1 ELSE 0 END) as Positive 
... 

Answer 2

select 
    DATE_FORMAT(created_at,'%d %M') as day, 
    count(*) as Total, 
    sum(if(content_sentiment = 0,1,0)) as Neutral, 
    sum(if(content_sentiment < 0,1,0)) as Negative, 
    sum(if(content_sentiment > 0,1,0)) as Positive 
from Master 
where content_sentiment IS NOT NULL 
GROUP BY DAY(created_at) 
;